Yes, installing full-extension drawer runners on existing drawers is a DIY-friendly job that most handy homeowners can tackle with basic tools, a bit of patience, and careful measuring. No building consent or licensed tradesperson is required — it's straightforward cabinetry work. That said, getting the alignment right is the part that trips people up, so read through the full process before you start.
What Are Full-Extension Drawer Runners?
Full-extension drawer runners (also called slides or glides) allow a drawer to pull out completely — 100% of its depth — so you can access everything at the back. They're a big upgrade over the old-style partial-extension runners found in many older NZ kitchens and laundries. Most modern full-extension runners are ball-bearing side-mount slides, though you'll also find undermount versions for a cleaner look.
Tools and Materials You'll Need
- Tape measure and pencil
- Square (combination square or try square)
- Cordless drill/driver with appropriate bits
- Screwdriver (usually Phillips #2)
- Level or spirit level
- Clamps (optional but helpful)
- The new drawer runners (sold in pairs)
You can pick up a good range of full-extension runners at Bunnings or Mitre 10. Look for runners rated to handle the load you need — kitchen pot drawers need a higher weight rating than a bedroom dresser.
Step 1 — Measure Carefully Before You Buy
This is the most important step. Measure:
- Drawer depth (front to back of the drawer box, not the face) — runners come in standard lengths such as 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, and 550 mm. Choose the length closest to (but not longer than) your drawer depth.
- Cabinet opening width — side-mount runners typically need 12–13 mm of clearance on each side between the drawer box and the cabinet wall. Check the manufacturer's spec sheet, as this varies.
- Cabinet opening height — make sure there's enough vertical space for the runner hardware.
If your drawer box is too wide for the new runners, you may need to trim it down or fit spacers — a job a local cabinet maker can do quickly if needed.
Step 2 — Remove the Old Runners
Unscrew and remove the existing runners from both the drawer box and the cabinet carcass. Fill any old screw holes with a suitable wood filler if they'll be in the way of your new fixings, and let it dry fully before drilling.
Step 3 — Separate the Runner Components
Most ball-bearing side-mount runners separate into two parts: the cabinet member (fixed to the cabinet wall) and the drawer member (fixed to the side of the drawer box). Slide them apart — there's usually a release lever or tab.
Step 4 — Fit the Drawer Members
Attach the drawer member to each side of the drawer box:
- Position it flush with the front of the drawer box (not the decorative face, if fitted separately).
- Keep it level and at the correct height — typically centred on the drawer side, but check your runner's instructions.
- Use the pre-drilled holes in the runner and drive screws firmly but don't overtighten into the timber.
Step 5 — Fit the Cabinet Members
This is where accuracy really matters:
- Mark a level line on each cabinet wall at the correct height. Both sides must be at exactly the same height or the drawer will rack and bind.
- Use a spirit level across the opening to confirm both marks are level with each other.
- Screw the cabinet member to the wall of the carcass, again starting from the front.
- Most runners have slotted holes for minor adjustment — don't fully tighten until you've tested the fit.
Step 6 — Test, Adjust, and Tighten
Slide the drawer into the cabinet members. Open and close it several times. A well-fitted full-extension runner should:
- Glide smoothly with no binding or wobbling
- Stay level when open
- Close fully without catching
If it's stiff or uneven, loosen the cabinet member screws and use the adjustment slots to shift the runner up, down, or sideways until it runs true. Once happy, tighten all screws fully.
Common Mistakes to Avoid
| Mistake | Result | Fix |
|---|---|---|
| Runners not level with each other | Drawer tilts and binds | Re-check with a spirit level across both sides |
| Runner length too long | Drawer won't close | Choose correct length for drawer depth |
| Screws into old filled holes before fully cured | Poor fixing | Allow filler to cure fully, or drill offset |
| Ignoring weight rating | Runner fails under load | Check kg rating before purchase |
| Drawer box too wide | No clearance for runners | Trim drawer box or use thinner runners |
Undermount Runners — A Note
Undermount runners are fitted beneath the drawer box and are largely hidden. They give a premium look but are more complex to fit, often requiring a specific drawer box thickness and a notch or clip system. If your existing drawer boxes weren't built for undermount runners, retrofitting them can be tricky. This is a case where consulting a cabinet maker first is worthwhile.
When to Call a Professional
While this is generally a DIY-friendly job, consider calling a qualified cabinet maker if:
- Your drawer boxes are damaged, warped, or out of square
- You're fitting undermount runners to existing boxes not designed for them
- The cabinet carcass itself is damaged or not plumb and level
- You're fitting runners to a large number of drawers and want a fast, guaranteed result
Cabinet making is not restricted work under NZ law, so there's no licensing requirement — but experience makes a real difference in fit and finish. You can find qualified local cabinet makers on tradedirectory.co.nz.
